diff --git a/napi/src/js_values/mod.rs b/napi/src/js_values/mod.rs
index c2eb7d63..ad700ba0 100644
--- a/napi/src/js_values/mod.rs
+++ b/napi/src/js_values/mod.rs
@@ -610,9 +610,11 @@ impl JsUnknown {
 
   #[inline]
   /// # Safety
+  ///
   /// This function should be called after `JsUnknown::get_type`
+  ///
   /// And the `V` must be match with the return value of `get_type`
-  pub unsafe fn cast<V>(self) -> V
+  pub unsafe fn cast<V>(&self) -> V
   where
     V: NapiValue,
   {